Circuit breaker spring switch arm



FIG. l.

A. B. RYPINSKI Filed Aug. l2, 1964 ATTORNEY.

Febf 7, 1967 CIRCUIT BREAKER SPRING SWITCH ARM United States Patent @hice Patented Feb. 7, i967 3,303,312 CRCUT BREAKER SPRING SWITCH ARRI i Albert E. Rypinsid, 233 E. 69th St.,

New York, NX. 16621 Filed Aug. l2, 1964,Scr. No. 339,158 Claims. (Cl. 29d- 166) This invention relates to the art of electrical circuit breakers, more particularly to an improved switch arm for a circuit breaker in -which the necessary dimensioning of the switch arm to provide desired current carrying capacities for the arm does not interfere with the spring action of the arm, or the forces necessary to effect de sired positioning of the arm.

As disclosed in applicants copending application S.N. 328,899, a variety of circuit breaker constructions have been evolved in which the presence of an overload current condition in the circuit in which the breaker is connected serves to trip a linkage which permits a switch arm to be displaced so as to interrupt or break the c1rcuit. As shown in this copending application, this current carrying switch arm is formed of a strip of spring copper, spring bronze, or the like electrically conducting material having desired spring properties. The switch arm is arranged for movement between a circuit making and circuit breaking position, and is held in the circuit making position so long as desired circuit conditions are maintained. Upon the occurrence of an undesired circuit condition, the linkage is tripped whereupon under the action of the spring biasing of the switch arm, it 1s moved to a circuit breaking position.

Thus as shown in this copending application, a switch arm of springy conducting material is contoured so as to be bent back on itself, and is positioned in a circuit breaker housing with one end connected to the magnetic coil and the other end left free to be moved from a posi tion touching, and a position remote from a xed contact button. This construction is adequate for circuit breakers of relatively small ampere capacities, such for example as l5, 2() and 30 amperes, but as the ampere capacities are increased, such for example to 40 and 100 amperes, the switch arm must be made sufficiently thick so as to carry the current without overheating This increase in thickness results in a reduction of desired spring action. Available materials such as spring copper, and various bronzes, when made thick enough to carry these higher ampere loads are often stressed to a point near or beyond their elastic limits when moved between a circuit making and circuit breaking position, Additionally, the heavier materials required for higher currents require greater pressures by the link train components to effect switch arm movement and unduly increase the necessary tripping pressures.

It is with the above problems and desiderata in mind, that the present means have been evolved, means providing for an'improved switch arm in which desired current carrying capacities are obtained Without interfering with desired spring action of the arm.

It is accordingly a lprimary object of this invention to provide an improved switch arm construction for an electrical circuit breaker.

A further Object of the invention is to provide an im proved switch arm in which the necessary dimensioning of the arm to accommodate different ampere capacities does not interfere with the desire dspring action of the arm.

An additional object of the invention is to provide an improved switch arm for a circuit breaker in which a variety of different `current carrying capacities may be accommodated in circuit breakers employing trip linkages of the same dimension and force transmitting capacity.

These and other objects of the invention which will become hereafter apparent are achieved by forming a switch arm assembly comprising a current carrying component or element and a spring component or element. The current carrying element may be selectively formed of a material and dimension such as to accommodate the desired current capacity of the breaker, while the spring element is formed of a material and dimension such as to provide necessary spring movement of the switch arm between a circuit making and circuit breaking condition. A contact button on the free end of the switch arm assembly is electrically connected to the current carrying member and is oriented for movement against the conventional relatively stationary contact button of the circuit breaker. The other end of the switch arm is anchored with respect to the housing ofthe circuit breaker, with the current carrying element electrically coupled to the current carrying components of the circuit breaker, which in the case of a magnetic circuit breaker will be the coil. An abutment element is formed on the switch arm for engagement by the trip linkage of the circuit breaker.

A feature of the invention resides in the formation of the improved circuit breaker switch arm of a two-part construction in which the current carrying element and the spring element are maintained in assembled relationship by the contact button aixed on the free end `of the arm.

Another feature of the invention resides in the fact that materials such as braided pigtail conductors may be employed in forming current carrying element in which the liexibility of the current carrying element does not interfere with the spring action of the switch arm.

A further feature of the invention resides in the use of the abutment element which may be contoured as desired, independently of the shape of the switch arm, to elifect desired coaction between the trip linkage and the switch arm. The abutment element due to its formation of spring material serves to accommodate any wear of the contact buttons due to arcing or the like.

The specific details ot several embodiments of the invention, and their mode of functioning will be made most manifest and particularly pointed out in clear, concise and exact terms in conjunction with the accompanying drawings, wherein:

FIG. l is a schematic cross-sectional view through a magnetic circuit breaker provided with the improved switch arm; and

FIG. 2 is an enlarged perspective exploded view of the components of the improved switch arm; and

FIG. 3 is a detail view or" another embodiment of a switch arm in accordance with the teachings of this invention.

Referring now more particularly to the drawings, like numerals in the various figures will be employed to designate like parts.

As shown illustratively in FIG. l, a circuit breake 1t) of the type more fully described in applicants copending application S.N. 328,899 is provided with an improved switch arm embodying the teachings of this invention. Circuit breaker 10 is formed with a casing 11 dimensioned to t the conventional load center panel. A clip connector 12 is exposed at one side of the casing 11 for engagement by the blade of a bus bar of the conventional load center. This connector 12 forms one end of an electrical circuit comprising conductor 13 leading from the clip connector 12 to solenoid coil 14. The other end of solenoid coil 14 is electrically coupled to conducting element 2G of the switch arm,`and movable contact button 21 secured to the opposite end of conducting element 20. Fixed contact button 22 is connected to wire connector 23 having a portion exposed by the casing 11 and provided with a machine screw 24 beneath the head of which a wire may be anchored.

The switch arm 25 made in accordance with the teachings of this invention, and as illustratively shown in FIGS. l and 2 comprises the conducting element 20 formed of a flexible conducting braid or pigtail comprising a mesh of intertwined strands of relatively soft, fine copper wire. Spring element 26 of the switch 25 is formed of spring steel or the like spring material and is contoured as illustrated in FIGS. l and 2. Offset end 27 of spring element 26 is secured in anchoring block 28 formed in the Casing 11, as illustrated in FIG. l. An anchoring loop 3G is formed on the end of conducting element 20 adjacent otfset end 27 of the spring element. Anchoring loop 30 is dimensioned such as to accommodate the free end of the wire forming oslenoid 14, it being intended that the ywire be inserted into the anchoring loop and affixed thereto to effect a suitable electrical circuit connection.

The free end 31 of the spring element 26 is formed with prong 32, and the free end 33 of conducting element 20 is formed with a similarly dimensioned prong 34. Movable contact button 21 is formed of a suitable electrically conducting material such as copper, bronze, or the like metals or alloys. Contact button 21 is shaped `as illustrated, and is provided with upstanding ears 40, 41, 42, 43, one at each corner thereof, with the spacing between the ears being such as to permit the prongs 34 and 32 to be seated therebetween. The ears are then swedged over the prongs 32 and 34 to secure the spring element 26 and conducting element 2t) in assembled relationship as illustrated in FIG. l.

An abutment element 44 is formed on switch arm 25 by bending the spring' element back on itself, as best seen in FIG. 2. Abutment element 44 is shaped to provide a surface cooperating with the switch linkage.

Movement of the switch arm 25 between the solid line circuit breaking position illustrated in FIG. l to the dot dash line circuit making condition is effected in the illustrated embodiment of the invention by a trip linkage 45 as more fully described in applicants copending S.N. 328,899. It will of course, however, be understood by those skilled in the art that the improved switch arm may be utilized in conjunction with a variety of different types of circuit breakers or other switching mechanirns. The trip linkage 45 comprises a bell crank lever link 46 having a downturned end 47 subject to engagement by armature 48 which is moved under the influence of solenoid coil 14. A slide member 49 moves against abutment 44 formed by the return bend of the spring element 27 of the switch arm 25. The handle 50 pivoted in casing 11, and formed integral with cam foot 51 permits selective manual movement of the lever link 46 against the upwardly biasing action of spring 53 to force slide member 49 against abutment 44 to move switch arm 25 to the dot dash position illustrated in FIG. l, bringing movable contact button 21 into contact with fixed contact button 22 thus completing the circuit through the circuit breaker between clip connector 12 and wire connector 23.

In the embodiment of the invention illustrated `in FIG. 3 `the switch arm 75 is shown as comprising a current carrying element 76 which is preferably formed of a springy yelectrically conducting material such a spring bronze or the like. This current carrying element 76 is sandwiched between a spring copper strip 77 folded over to provide an anchoring loop 78 within which the conductor from solenoid 14 may be secured. A return bend 80 in conducting element 76 permits the formation of an abutment 81 against which slide member 49 may be moved. In this FIG. 3 embodiment the spring element 77 is coterrninous with the ends of the current carrying element so that a part of the current fed to conducting element 76 may be (carried by the spring Yelement 77.

4 Operation The aforedescribed improved switch arm may be employed in a variety of situations where it is necessary to provide a current carrying arm to effect desired switching functions in which the movement of the arm is effected by spring action and serves to make or break a circuit in which the arm is connected. By use of the insta-nt arm, desired current carrying capacities may be obtained without interfering with desired spring action.

In the illustrated embodiment, the switch arm either of the type shown in FIGS. l and 2, or in the form of alternative embodiment shown in FIG. 3 may be employed as the switch arm of a circuit breaker. Where so employed. the current carrying element 20 of the FIGS. l and 2 embodiment is coupled into the electrical circuit through the circuit breaker' by connecting the end of solenoid 14 through anchoring aperture 30, and mounting ear 27 in anchoring block 28 of the casing 11.

When the handle 5t) is moved to bring cam foot 51 against lever link 46 the slide member 49 moves against abutment 44 forcing the switch arm to the dot dash position in which movable contact button 21 touches xed contact button 22 to complete the circuit through the circuit breaker.

By providing abutment 44 on the spring element 26, the abutment 44 may be precisely shaped to give the optimum movement to the spring under the inuence of slide member 49. Without this abutment, the spring element 26 would have to be shaped to meet desired conditions, and the shaping of the spring would interfere with desired spring action. Additionally the spring action of the abutment serves to accommodate any wear of the contact buttons.

In the alternate construction shown in FIG. 3 the conducting element 76 due to its springy nature aids in the spring action of the switch arm, and due to the fact that the spring element 77 is integral with anchoring loop 78, the spring element 77 aids in the conducting action.

It is thus seen that an improved switch arm has been provided in which an increase in the diniensioning of the current carrying element of the arm such as is required to increase the current carrying capacity of the arm does not interfere with the spring action thereof.

The above disclosure has been given by way of illustration and elucidation and not by way of limitation, and it is desired to protect all embodiments of the herein disclosed inventive concept within the scope of the appended claims.

What is claimed is:

1. A switch arm comprising: a conducting element electrically coupled into a circuit; a contact button on said conducting element; and a spring element coupled to said contact button arranged adjacent said conducting element in biasing relationship to said contact button to displace said conducting element from a circuit making condition.

2. A switch arm as in claim 1 in which an abutment element is secured to said arm, said abutment element shaped independently of said arm.

3. A switch arm as in claim 1 in which said spring element is anchored at an end thereof remote from the conducting element.

4. A switch arm as in claim 1 in which said spring element and said conducting element are coterminous.

5. In a circuit breaker: a stationary contact member; a movable contact member arranged to move from a position against said stationary contact member to a position removed therefrom to make and break a circuit through said circuit breaker; a switch arm supporting said movable contact member, said swtich arm comprising: a conducting element electrically coupled to said movable contact member; a spring element coupled to said movable contact member and biasing same away from said stationary contact member; one end of said spring element xedly secured with respect to said circuit breaker; a trip linkage movable with respect to said switch arm to force same lo a position bringing said movable contact member against said stationary contact member; and means tripping said linkage to permit the spring action of Said spring element to move said movable contact member away from said stationary contact member.

6. In a circuit breaker as in claim 5, said movable contact member comprising: a Contact button secured to said spring element and said conducting element.

7. In a circuit breaker as in claim 5, an abutment element secured to said arm against which said trip linkage is movable.

` 8. In a circuit breaker as in claim 5 in which an anchorying block is formed in said breaker in which the end of said spring element is secured.

9. In a circuit `breaker as in claim 5 in which said spring element and said conducting element are coterrninous 10. IIn a circuit 'breaker having a trip linkage subject to actuation by the flow of undesired current through a current carrying element in the breaker, a Xed contact supported in said breaker, and a movable contact movable to and from said xed contact to make and break the circuit through said breaker: a conducting switch arm assembly having one end xedly secured with respect to the breaker and another end upon which said movable contact is mounted; a spring element extending substantially along the length of said switch arm biasing said switch arm to a position bringing said movable contact away from said fixed Contact; and an abutment on said siwtch arm against which said trip linkage acts to bring said switch arm -to a position bring said movable contact into current carrying relationship with respect to said xed contact.

References Cited by the Examiner UNITED STATES PATENTS 2,071,848 2/'1937 Lindstrom ZOO-116 2,294,196 8/1942 Moore 20G-'19 2,521,887 9/1950 Wihanto 200-19 z2,890,306 6/1959 Rypinski et al 2G0-88 X ROBERT K. SCHAEFER, Primary Examiner. ROBERT S. MACON, Examiner.

H. O. JONES, Assistant Examiner. 

1. A SWITCH ARM COMPRISING: A CONDUCTING ELEMENT ELECTRICALLY COUPLED INTO A CIRCUIT; A CONTACT BUTTON ON SAID CONDUCTING ELEMENT; AND A SPRING ELEMENT COUPLED TO SAID CONTACT BUTTON ARRANGED ADJACENT SAID CONDUCTING ELEMENT IN BIASING RELATIONSHIP TO SAID CONTACT BUTTON TO DISPLACE SAID CONDUCTING ELEMENT FROM A CIRCUIT MAKING CONDITION. 